Apparatus for producing curly glass fibers

ABSTRACT

An apparatus for producing curly fibers from a molten stream which is pulled from a melt by high velocity attenuating fluid. The device includes a fiber forming feeder having orifices extending between a pair of elongate blowers which direct intersecting streams of high pressure fluid below the orifices to attenuate and cool the molten streams into fibers. Positioned below the orifices is a single skirt extending generally parallel to the direction of movement of the fibers and having a plurality of sinuous convolutions. High velocity air streams pulling the plastic fibers across the convolutions cause them to impinge against one or more skirt convolutions and to assume a curvilinear configuration prior to losing plasticity and leaving the skirt area. The skirt may be surrounded by a peripheral housing having air vents which permit the lateral entry of outside air pressure to further assure contact between the skirt and descending fibers.

Unite States Patent Stalego et all.

[451 Apr. 4, 1972 [54] APPARATUS FOR PRODUCING CURLY GLASS FIBERS [72]Inventors: Charles J. Stalego; Robert E. Wyckolf,

both of Newark, Ohio [73] Assignee: Owens-Corning Fiberglas Corporation22 Filed: Aug. 27, 1970 21 Appl. No.: 67,442

Primary Examiner--S. Leon Bashore Assistant Examiner-Robert L. Lindsay,Jr. Attorney-Staelin & Overman and Vincent L. Barker, Jr.

[57] ABSTRACT An apparatus for producing curly fibers from a moltenstream which is pulled from a melt by high velocity attenuating fluid.The device includes a fiber forming feeder having orifices extendingbetween a pair of elongate blowers which direct intersecting streams ofhigh pressure fluid below the orifices to attenuate and cool the moltenstreams into fibers. Positioned below the orifices is a single skirtextending generally parallel to the direction of movement of the fibersand having a plurality of sinuous convolutions. High velocity airstreams pulling the plastic fibers across the convolutions cause them toimpinge against one or more skirt convolutions and to assume acurvilinear configuration prior to losing plasticity and leaving theskirt area. The skirt may be surrounded by a peripheral housing havingair vents which permit the lateral entry of outside air pressure tofurther assure contact between the skirt H and descending fibers.

12 Claims, 5 Drawing Figures Patented A ril 4, 1972 3,653,861

2 Sheets-Sheet l 67mm 55 J. Sm 60 & R055 WVC/(GFF 1N VENTORS Y m amJTTOPA/l-TYS APPARATUS FOR PRODUCING CURLY GLASS FIBERS BACKGROUND OFTHE INVENTION This invention relates to an apparatus and process forproducing curly glass fibers which, after formation, may be collected ona conveyor in mat form and subsequently used in low density pack form asa filter for air or other fluids.

It is known in the prior art that curly fibers of a heat softenablematerial may be formed by attenuating streams of molten glass from agroup of fiber forming orifices by streams of high velocity fluid in apath generally parallel to the direction of glass flow between a pair ofcorrugated plates or skirts extending the length of the orifice groupalong either side of the air flow. Such an arrangement, which is shownin US. Pat. No. 2,927,621 to Slayter et al., uses the turbulence of thefluid flow below the orifices or bushing to direct the fibers whilestill in a plastic state against the corrugated skirts on either side.When the plastic fibers strike these skirts, they impinge upon one ormore skirt corrugations to assume a curly configuration which isretained as the fibers are cooled on their downward path towards acollection point. While apparatuses such as that shown in theaforementioned Slayter et al patent have operated satisfactorily tocommercially produce such curly fibers, several difficulties inproduction are encountered which reduce the output from suchinstallations and cause undesirable downtime and maintenancedifiiculties. One such difficulty is caused by the fact that the lateraldistance between the plates, in order to assure fiber impingement by themajority of the fibers in the stream, is such that certain fibersstriking the plates may ricochet from the plate on one side across tothe other side, thus completely blocking the path for other fibers. Thiscan quickly cause a fiber build-up between the plates which necessitatesremoval of the build-up prior to further fiber formation. Anotherdifficulty caused by the presence of the two closely spaced plates oneither side of the orifice group is the difficulty of inspecting theorifices themselves visually from below which needs to be done on afrequent basis to assure that they are operating properly. Finally, thepresence of two closely spaced opposed skirts sometimes results in theformation of shot or small particles of hot glass which are caused byfiber impingement upon each of the plates or build-ups as previouslyexplained.

SUMMARY OF THE INVENTION It has been discovered that curly fibers foruse in filter media and the like can be satisfactorily formed at highspeed in an installation in which a single skirt positioned on one sideof the orifice group is used, thus obviating several of thedisadvantages in the prior art installations. In this apparatus, thesingle skirt is positioned below the blowers, extending along one sideof the orifice group, with the fiber and fluid stream moving generallyparallel to the surface of the skirt. Surrounding the skirt on all foursides is a housing having lateral openings opposite the faces of thesingle skirt so that air may be induced through these openings laterallyinto the skirt area. This induced lateral air causes the stream offibers to impinge upon and generally assume the configuration of thecorrugated skirt surface, thus causing them to take a curved ornonlinear shape while in their plastic state. The ends of the singleskirt terminate short of the opposed ends of the housing so that inducedair flow coming around the skirt ends will prevent the fibers frommoving outwardly and piling up at the ends of the skirt. Otheradvantages and details of the invention will be apparent from thedetailed description below.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a view in perspective of afiber forming assembly of the instant invention, schematically showing asingle row of fiber forming bushings, a pair of blowers fortheattenuating air, and the single skirt depending from one of the blowerhousings surrounded by a downwardly extending housing:

FIG. 2 is an end view of the skirt and flow of fibers, indicatingschematically the curling action of the fibers as they pass downwardlyalong the skirt;

FIG. 3 is a view in perspective of a single skirt assembly of thisinvention, similar to FIG. 1 but showing a different skirtconfiguration;

FIG. 4 is a view in elevation of the skirt shown in FIG. 3, indicatingschematically the path of the fibers moving downwardly along the skirt;and

FIG. 5 is a view of the skirt configuration of FIGS. 3 and 4, takenalong 55 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION Referring first to FIG. 1, asingle row or group of fiber forming orifices 10 in a feeder is shownschematically, with the axis of each orifice extending parallel to eachother in a vertical plane. On either side of the vertical plane of theorifice axes is positioned a pair of blower housings l1 and 12 connectedto a blower manifold 13 through which is supplied a source of highpressure attenuating fluid, such as air or steam. The outlets of theblower housings 11 and 12, indicated by reference numeral 14, areelongate openings extending alongside the row of orifices and arepositioned to direct the flow of attenuating fluid downwardly andslightly inwardly so that the fluid flow from the outlets 14 willintersect the plane of the orifice axes at a point somewhat below theblowers. In preferred practice, the included angle between this planeand each of the blower outlets 14 is about twelve degrees.

Extending from the lower portion of the blower housing 11 is a singleskirt 15 which, as best seen in FIG. 2, has its uppermost portionsecured to the lower surface of the blower housing 11. This skirtincludes a plurality of parallel extending wavy corrugations or sinuousconvolutions, as seen in FIG. 2, whose crests, on the fiber side of theskirt, are generally in vertical alignment with the uppermost portion ofthe skirt 15. The distance between these crests of the skirt 1S and theplane of the orifices preferably is about one-eighth of an inch. Thisdistance can be adjusted by use of a conventional mechanism (not shown),such as a simple slot and set screw, or by a more convenient type ofadjusting mechanism such as that shown in the aforementioned Slayter etal patent. This lateral adjusting mechanism does not form a part of thepresent invention.

Surrounding the skirt 15 below the blowers 11 and 12 is a dependinghousing 16 having opposed ends 17 and 18 on each end of the orifice row10, a perforate side 19 and a louvered side comprised of horizontallyextending blinds or louvers 20. As seen in FIG. 1, the single skirt 15does not extend the entire length of the blower housings 1 1 and 12 sothat there is a space between each end of the skirt and its opposed end17 or 18 of the housing 16.

The perforate side 19 of the housing 16 is provided with fluid passageswhich admit outside air into the space adjacent the rear wall of theskirt 15. This air, which is induced by the high pressure air flowingalong the front face of the skirt from the blowers, can pass aroundeither end of the skirt 15 between the skirt ends and the opposed ends17 and 18 of the housing 16 to keep the fibers from migrating away fromthe center of the skirt 15 towards the ends. This is important toprevent a fiber build-up at the ends of the skirt 15.

The horizontal louvers 20, which form the side of the housing oppositethe front or fiber face of the skirt, may be adjusted by pivoting themon their horizontal axes to vary the amount of outside air which isinduced laterally through the louvers 20 into the space adjacent thefront of the skirt 15. This is the primary flow of lateral air whichcauses the fiber curling phenomena illustrated in FIG. 2. In FIG. 2, asthe molten metal issues from the orifices 10, it is drawn downwardly bythe streams of attenuating air, as shown, to the area of corrugations inthe skirt 15. As the fibers proceed downwardly, the primary flow ofattenuating air, which has been produced by the intersecting streamsfrom the blower outlets 14, becomes somewhat turbulent as it approachesthe upper valley or reverse crest 21 of the skirt 15. At the same time,lateral air, indicated by the arrows coming through the louvers 20,strikes the mass of fiber flow and causes it to open and impingeindividual fibers upon the first crest portion of a corrugation,designated by reference numeral A on the skirt. The sinuous corrugationsare shaped such that the impiagement surface at area A is at less than aright angie to the direction of fiber movement. As soon as a few fibersimpinge at the area A, they are slowed down, causing other fibers toimpinge against them, which. creates random movement among the movingfibers causing a substantial number of the fibers to curl as theirmovement downwardly is impeded. As the downward movement of these fibersprogresses, certain ones impinge upon the next successive crest portionsof the corrugations, B or C, to further create random intermingling andcurling of all the fibers. In each case, the lateral air coming throughthe louvers 20 assists in causing the fibers to be randomly drawnagainst the portions A, B or C of the skirt. When the fibers reach thelowermost portion of the skirt 15, they have cooled to the point wherethey are no longer plastic but retain their desired non-linearconfiguration.

It will be seen that the effect of the lateral air flow from the louvers20 is to drive certain ones of the fibers into the valley portions ofthe corrugations extending away from the crests A, B and C, whichassures their impingement upon the portions A, B and C as they movedownwardly. Thus the single skirt of this invention is not necessarilyplaced directly within the fiber flow but can be spaced therefrom by asmall amount and utilize the lateral air flow to assure impingement.

Another embodiment of the instant invention is illustrated in FIGS. 3, 4and 5, where like reference numerals are used for like parts. Theembodiment of FIGS. 3, 4 and 5 is essentially similar to that shown inFIGS. 1 and 2 except for the direction of the corrugations or sinuousconvolutions of the skirt 15. In this embodiment, the parallel extendingcorrugations of the skirt are generally vertical, that is, their crestsand valleys extend parallel to the general movement of the fibers. Thephenomena of curling in the embodiment is illustrated in FIG. 4 which,in a view in elevation, shows the planar mass of fibers movingdownwardly along the skirt. In this embodiment, lateral air through theopen louvers causes certain of the fibers to strike the crests of theconvolutions, as was the case with the embodiment of FIGS. 1 and 2.After striking, the fibers are moved either to the left or the right, asshown in FIG. 4, to be opposite a valley on either side of a crest. Whenthis happens, other fibers coming down along the valley strike thesefibers and are moved to the left or the right to further become curledby striking still other fibers or the crest portion of the corrugations.In this embodiment, fiber. interaction is improved and the possibilityof fiber build-up and shot formation is virtually eliminated. As was thecase with the previous embodiment, the edges of the skirt 15 are spacedfrom the opposed ends 17 and 18 of the housing so that lateral airthrough the perforations in the side plate 19 is drawn around the edgesof the skirt to keep the fibers from building up at the edges.

From the above description of two embodiments of the im stant invention,it can be seen that the assembly using a single skirt below a fiberforming bushing has certain advantages over the prior art and alsorelies upon a somewhat different fiber formation process. Rather thanhaving two opposed skirts which cause alternate impingement of thefibers as they proceed on their downward path, the instant inventionusing a single skirt relies upon the phenomena of induced lateral air tocause the fibers to impinge one or more times upon the single skirt.This has the advantage of reduction of fiber build-up difficulties andshot formation and also reduces the number of parts in a giveninstallation while improving the ability of the operator to observe theprocess and inspect the bushings for possible malfunction.

Other advantages of the instant invention will be apparent to thoseskilled in the art and various modifications may be made withoutdeparting from the scope of the attached claims.

We claim:

1. An apparatus for producing curly fibers from attenuating streams ofmolten material comprising, in combination, an elongate group of fiberforming orifices having parallel extending axes in a generally verticalplane, a pair of elongate blowers adjacent said orifice group andpositioned to direct streams of high velocity attenuating fluid fromeach side of said group to intersect at a point below said group in saidvertical plane, a single depending rigid skirt extending alongside saidgroup generally parallel to said plane and below said group, said skirthaving a plurality of sinuous corrugations with spaced apart crestportions of successive corrugations extending toward said plane, andmeans for admitting amounts of induced air flow against said fibers in alateral direction towards said skirt whereby plastic fibers attenuatedby said stream will pass said skirt and impinge upon one or moreportions thereof prior to leaving said skirt area.

2. The apparatus of claim 1 wherein said skirt is surrounded on allsides by a peripheral housing having means defining openings laterallyadjacent each face of said skirt to cause gaseous flow from said blowersalong said plane to induce lateral air flow through said openings intosaid housing.

3. The apparatus of claim 2 wherein certain fluid openings in said skirthave means adjustable in area to vary the amount of lateral air flowinto said housing.

4. The apparatus of claim 1 wherein said sinuous corrugations of saidskirt extend across said orifice group in a generally horizontaldirection such that said spaced apart crest portions closest to saidplane are vertically spaced across the height of said skirt.

5. The apparatus of claim 1 wherein said sinuous corrugations of saidskirt extend across said orifice group in a generally vertical directionsuch that said spaced apart crest portions closest to said plane arehorizontally spaced across the length of said skirt.

6. The apparatus of claim 1 wherein said spaced apart crest portionsclosest to said plane are separated by alternate valley portions of saidsuccessive convolutions extending away from said plane to provide areastherebetween for fiber impingement upon said skirt at angles of lessthan normal to the direction of fiber flow.

7. An apparatus for producing curly glass fibers comprising, incombination, an elongate group of fiber forming orifices havinggenerally vertical axes, means for blowing high velocity fluid alongsidesaid orifices to attenuate said fibers flowing therefrom, a singledepending rigid skirt extending along one side of said group of orificesgenerally parallel to said fiber flow, said skirt having a plurality ofsinuous corrugations with portions of successive corrugations extendingtoward said fiber flow, and means for admitting amounts of induced airflow against said fibers in a lateral direction towards'said skirtwhereby plastic fibers attenuated by said fluid flow will pass saidskirt and impinge upon one or more portions thereof prior to leavingsaid skirt area.

8. The apparatus of claim 7 wherein said skirt is surrounded on allsides by a peripheral housing having means defining openings laterallyadjacent each face of said skirt to cause gaseous flow from said blowerto induce lateral air flow through said openings into said housing.

9. The apparatus of claim 8 wherein certain fluid openings in said skirthave means adjustable in area to vary the amount of lateral air flowinto said housing.

10. The apparatus of claim 7 wherein said sinuous corrugations of saidskirt extend across said orifice group in a generally horizontaldirection such that said spaced apart portions closest to said plane arevertically spaced across the height of said skirt.

11. The apparatus of claim 7 wherein said sinuous corrugations of saidskirt extend across said orifice group in a generally vertical directionsuch that said spaced apart portions closest to said plane arehorizontally spaced across the length of said skirt.

12. The apparatus of claim 7 wherein said spaced apart portions closestto said plane are separated by alternate portions of said successivecorrugations extending away from said plane to provide areastherebetween for fiber impingement upon said skirt at angles of lessthan normal to the direction of fiber flow.

1. An apparatus for producing curly fibers from attenuating streams ofmolten material comprising, in combination, an elongate group of fiberforming orifices having parallel extending axes in a generally verticalplane, a pair of elongate blowers adjacent said orifice group andpositioned to direct streams of high velocity attenuating fluid fromeach side of said group to intersect at a point below said group in saidvertical plane, a single depending rigid skirt extending alongside saidgroup generally parallel to said plane and below said group, said skirthaving a plurality of sinuous corrugations with spaced apart crestportions of successive corrugations extending toward said plane, andmeans for admitting amounts of induced air flow against said fibers in alateral direction towards said skirt whereby plastic fibers attenuatedby said stream will pass said skirt and impinge upon one or moreportions thereof prior to leaving said skirt area.
 2. The apparatus ofclaim 1 wherein said skirt is surrounded on all sides by a peripheralhousing having means defining openings laterally adjacent each face ofsaid skirt to cause gaseous flow from said blowers along said plane toinduce lateral air flow through said openings into said housing.
 3. Theapparatus of claim 2 wherein certain fluid openings in said skirt havemeans adjustable in area to vary the amount of lateral air flow intosaid housing.
 4. The apparatus of claim 1 wherein said sinuouscorrugations of said skirt extend across said orifice group in agenerally horizontal direction such that said spaced apart crestportions closest to said plane are vertically spaced across the heightof said skirt.
 5. The apparatus of claim 1 wherein said sinuouscorrugations of said skirt extend across said orifice group in agenerally vertical direction such that said spaced apart crest portionscloSest to said plane are horizontally spaced across the length of saidskirt.
 6. The apparatus of claim 1 wherein said spaced apart crestportions closest to said plane are separated by alternate valleyportions of said successive convolutions extending away from said planeto provide areas therebetween for fiber impingement upon said skirt atangles of less than normal to the direction of fiber flow.
 7. Anapparatus for producing curly glass fibers comprising, in combination,an elongate group of fiber forming orifices having generally verticalaxes, means for blowing high velocity fluid alongside said orifices toattenuate said fibers flowing therefrom, a single depending rigid skirtextending along one side of said group of orifices generally parallel tosaid fiber flow, said skirt having a plurality of sinuous corrugationswith portions of successive corrugations extending toward said fiberflow, and means for admitting amounts of induced air flow against saidfibers in a lateral direction towards said skirt whereby plastic fibersattenuated by said fluid flow will pass said skirt and impinge upon oneor more portions thereof prior to leaving said skirt area.
 8. Theapparatus of claim 7 wherein said skirt is surrounded on all sides by aperipheral housing having means defining openings laterally adjacenteach face of said skirt to cause gaseous flow from said blower to inducelateral air flow through said openings into said housing.
 9. Theapparatus of claim 8 wherein certain fluid openings in said skirt havemeans adjustable in area to vary the amount of lateral air flow intosaid housing.
 10. The apparatus of claim 7 wherein said sinuouscorrugations of said skirt extend across said orifice group in agenerally horizontal direction such that said spaced apart portionsclosest to said plane are vertically spaced across the height of saidskirt.
 11. The apparatus of claim 7 wherein said sinuous corrugations ofsaid skirt extend across said orifice group in a generally verticaldirection such that said spaced apart portions closest to said plane arehorizontally spaced across the length of said skirt.
 12. The apparatusof claim 7 wherein said spaced apart portions closest to said plane areseparated by alternate portions of said successive corrugationsextending away from said plane to provide areas therebetween for fiberimpingement upon said skirt at angles of less than normal to thedirection of fiber flow.